Metal spray gun



Oct. 27 1936. F. o. ALBERTSON METAL SPRAY GUN Filed April 50, 1936 2Sheets-Sheet 1 y -\%"raas' QflZZerZIsvza ,MykMgY-(M &

Oct. 27, 1936. F. o. ALBERTSON METAL SPRAY GUN Filed April 30, 1936 2Sheets-Sheet 2 Fatented Oct. 27, 1936 UNITED STATES PATENT OFFICE METALSPRAY GUN Frans 0. Albertson, Sioux City, Iowa, assignor to Albertson &Company, Inc., Sioux City, Iowa, a

corporation of Iowa 14 Claims.

The present invention relates to metal spray guns, and is particularlyconcerned with devices of the type adapted to spray cold metal upon aprepared metal surface.

It finds its most effective field of use in building up dents anddepressions upon the bodies of automotive vehicles without heating thebody metal, and in places formerly inaccessible for repair work exceptby long, tedious hand labor methods.

In straightening fenders and body parts it is not always possible to getthe surface entirely smooth. If such a surface is sanded until it iseven, certain spots on the metal will be almost sanded through untilthere is practically no metal left. This condition can now be avoided byapplying a thin layer of suitable metal alloy on the spot with a spraygun constructed according to the present invention and then sanding thearea to a smooth and even finish.

One of the objects of the invention is the provision of an improvedmetal spray gun which has provision for cooling the gun by means of thecompressed air used for the spray.

Another object of the invention is the provision of an improved metalspray gun by means of which the metal may be sprayed more effectively bya cold process so that the body of the car is not heated to such anextent that it would warp. .The cold spray method is also necessarybecause some bodies are now insulated with inflammable materials.

Another object of the invention is the provision of an improved metalspray gun having a novel control by means of which both the air and theheat are under the complete control of the operator.

Another object is the provision of an improved nozzle structure for ametal spray gun of the class described, having a particular structureadapted towithstand melting and having a shape which is more effectivethan the devices of the prior art.

Another object is the provision of an improved metal spray gun utilizingheat for the melting of the metal, which is so constructed that it ismore eflectively cooled and the handle parts are kept cooler than thedevices of the prior art.

Other objects and advantages of the invention will be apparent from thefollowing description and the accompanying drawings, in which similarcharacters of reference indicate similar parts throughout the severalviews.

Referring to the two sheets of drawings:

Fig. 1 is a side elevational view of the metal spray gun constructedaccording to the present invention;

Fig. 2 is a vertical sectional view taken on a plane passing through theaxis of the air tube,

REISSUED DEC 2 4 1940 with parts of the gum in elevation to show theinternal structure; i

Fig. 3 is a vertical sectfonal view, taken on the plane of the lines-Iof Fig. 2, looking in the direction of the arrows, and showing the endof the heating element housing;

Fig. 4 is a vertical sectional view taken on the plane of the line 4-4of Fig. 2, looking in the direction of the arrows and showing thedetails of construction and support of the valve housing on the handle;

Fig. 5 is a bottom plan view of the heating element housing and asectional view taken through the .heat radiating supports on the planeof the line 5-5 of Fig. 2, looking in the direction of the arrows;

Fig. 6 is a horizontal sectional view, taken through the handle andtrigger structure, on the plane of the line 6-6 of Fig. 2, looking inthe direction of the arrows;

Fig. '7 is a front elevational view of the nose. end of the gun.

Fig. 8 is an elevational view of a blow-out and clean-out tool;

Fig. 9 is a fragmentary sectional view, showing the application of thetool for blowing out the metal well.

Referring to Figs. 1 and 2, the handle member It! may be constructed ofcast metal, having any suitable shape for fitting the hand, and of suilicient length down to the finger-engaging shoulder I I, to accommodatethe entire hand.

The handle ID has a rearwardly curved surface l2 adapted to rest on thehand between the thumb and forefinger, and the handle is hollow andprovided with a box-like formation ll of substantially rectangular shapein plan at the top.

The handle has a groove It in its rear wall, the groove being ofsufllcient size to receive the rubber hose l5, which carries insulatedelectrical conductors l6, l1. Hose l5 has a resilient wire metal ring I8clamped about it in such manner that it also clamps the walls of thehose into engagement with the conductors l6, l1, and the ring 18 isengaged in a groove is formed in the handle cover plate 20.

The cover plate 20 comprises a plate of sheet metal which is formed witha substantially square guide aperture 2| and with other apertures forreceiving the screw bolts 22 which secure it on ,45 for passing thesquare push rod 41.

closed in Patent No. 1,889,259, issued November 29, 1932.

This switch unit has a threaded bore 25 for reception of a screw bolt 21passing through the forward wall of the handle and securing the switchunit in place. The switch unit may have secured to it a substantiallyU-shaped supporting member 28. U-shaped metal member 28 slidablysupports a slider 34, which is adapted to engage the tumbler oi the snapswitch 25 and actuate the snap switch. The slider 34 has a pair ofrearwardly projecting flanges 35, 35, the latter one being punched outof the body 34.

Flanges 35, 35 embrace a pin 31, which pin is carried by the rearwardlyprojecting cars 38 of the trigger 39. The pin 31 is urged downwardly bya pair of coil springs 40, one located on each side of the U-shapedmember 28, the ends of each coil spring being hooked over the pin 31.The opposite end of each coil spring is secured by a screw 4| to theU-shaped member 28. The U-shaped member 28 also carries a bracket 33.comprising a strip of metal, also secured by the screw 2'! and extendingupwardly into the body of the handle Hi. This bracket 33 has arearwardly turned flange 42, which is secured by a screw bolt 43 to asupporting plate 44. Support ing plate 44 is secured in the box-likehousing |3 by a pair of screw bolts 45.

Plate 44 and flange 42 both have apertures The bracket 33 has a pair ofrearwardly projecting flanges 48, with apertures for slidably supportingthe plunger 29. Plunger 29 comprises a pin having a washer 30 riveted onone end to retain it in the flanges 48. The other end of the plunger hasa knob 32, and a spring 3| is compressed between the knob 32 and aflange 48.

Spring 3| constantly urges the plunger 29 downwardly in Fig. 6 so thatWasher 30 tends to engage flange 48. The trigger 39, however, has ashoulder 58 so arranged that when the trigger is pulled and the button32 is pressed, the plunger 29 may engage the shoulder 58 to hold thetrigger in closed circuit position.

The trigger is normally in open circuit position, as shown in Fig. 2,and the switch is closed by pulling on the trigger. When the plunger 29is engaging the shoulder 58 of the trigger, the washer 3D isengaging theside of the flange which forms the shoulder 50 on the trigger, as shownin Fig. 6. This causes the washer 30 to bind against the trigger flangein such manner that plunger 29 constitutes a releasable latch. It isnecessary not only to press upon the button 32,

but to press on the trigger sufliciently to disengage the trigger fromunder the washer 30; that is, the trigger must be pulled in far enoughso that the shoulder 50 clears the washer 38 before the trigger can thenagain be released to shut off the switch 25.

It will be evident that the trigger can be held in closed position, andupon release it moves the switch to open position, but it can also belatched in closed position, and can then be released by simultaneouslypressing the knob 32, and then pulling and releasing the trigger whilethe knob is held.

The same trigger 39 also controls an air valve in such manner that bothof the sources of power required for operating the spray gun arecontrolled by the same trigger.

This control is efiected through the push rod 41, which extendsdownwardly through the apertures 46 and 2| and engages the slider 34.The

push rod extends upwardly throughfurther guide apertures 2| in thesupporting plates 5|, andis adapted to engage the stem 52 of an airvalve 53.

The air valve 53 is a substantially cylindrical body slidably mounted ina plug 54, which is carried by the metal body 55. Plug 54 may beconstructed of brass and provided with a suitable seat 55 for engagingthe complementary irustoconical seat on the valve body 23. The plug 54may be a close frictional lit in a bore 51 in the body 55.

A coil spring 58 is contained in the bore 59 ot plug 54 and engages thevalve body 53. The spring is placed under compression by a screw plug 50which is threaded into the counterbore in the plug 54 and engages theend of the spring. The valve body 53 and seat 55 are so constructed thatthey have an initial clearance or opening so as to provide for theleakage of air through the spray gun whenever the air is turned on. Thisis a very important feature for efiecting the cooling of the gun andpreventing the nose of the gun from getting too hot.

The body 55 is best shown in Fig. 4, and it comprises an invertedtrough-shaped cast metal member, the walls of which have a multiplicityof apertures 5|. The member 55 has a depending body 52 in the trough,which is adapted to serve as an air conduit, having a bore 53, which maybe provided with a counterbore for receiving the air fitting 54.

Conduit 53 communicates with a transverse bore 55 extending through theplug 54, and on the other side of the plug the conduit receives the endof a brass tube 55 for conducting air to a nozzle. The brass tube issecured in the body by means of a set screw 51, which engages the brasstube. The push rod 41 is adapted to engage the end of the valve stem 52to open the air valve whenever the current is turned on. For thispurpose the push rod 41 is suitably spaced from the stem 52 to permitsufiicient movement by merely opening the valve 53 slightly with thetrigger 39.

The valve spring 58 also serves to return the push rod 41 to itsposition, although the push rod is also actuated by gravity. The body 55is supported upon the handle III by means of a plurality of screw bolts58. The box-like formation i3 has its walls thickened at each cornersufiiciently to provide metal for a bore 59 that passes the heads 10 ofthe screw bolts 58. The heads 15 engage the lower surface of the plate20, which is secured in place on the box 3 by screw bolts 22. Thus thescrew bolts 58 may pass through the plate 20 and be threaded into thebores H in the body 55.

Screw bolts 58 also support the heat radiating spacers 12, which areplaced on the screw bolts and interposed between the plates 20, 5|.

The upper plate 5| serves as a closure for the U-shaped trough members55. and is also secured in place by screw bolts 58. The member 55 mayalso be provided with a supporting eye member comprising a pair of sheetmetal angle members I3. The feet of these angle members are secured tothe top of the body 55 by screw bolts 14 and their upwardly extendingflanges are provided with registering apertures 14, I5.

The apertures 15 may be used to engage a hook or other supporting memberso that the gun may be hung up when hot or at any other time.

The valve housing 55 has a substantially rectangular opening 16 at itsforward or left end in Fig. 2, bounded by the trough-like walls 11. Thisrectangular opening. is adapted to receive the metal spacer 18, which isa; tube located on the brass tube 88. It also receives the porcelainspacer 19, which is of sumcient size to fit in the rectangular opening15 and which has a bore for passing the brass tube 85. 1

The porcelain spacer 19 also has a pair of transverse apertures in theform of slots for passing the electrical conductors or leads 23 thatextend to the terminals 8| of the heating element 82. The heatingelement 82 comprises a helical coil of nichrome wire or other suitableresistance wire, which is wound helically upon a porcelain spool 83.

The porcelain spool 83 has hemi-cylindrical grooves 84 for receiving thecoiled wire 82, and the grooves progress helically on the spool. One endof the heating coil wire is connected directly to a terminal 8| at theright end, while the opposite end of the wire is led through abore 85 inthe spool to the other terminal 81.

The body 83 has a bore 88 formed in it for passing the brass air tube55, and the heating element is supported by means of this tube. Theheating element is housed in a cast metal body 81, which has asubstantially trough-like chamber 88 in its interior. This chamber isopen at the right end of Fig. 2 and has a substantially rectangularopening at that poiiit for receiving and engaging the fiat sides ofthespacer 19 as well as the flat sides 89 carried by the end of theporcelain body 83. This prevents rotation of the porcelain body 83 onthe tube 55.

The trough-like chamber 88 is closed at the bottom by means of a metalplate 98, which may comprise a name plate of the tool, and is secured inplace by screw bolts 9|.

At its forward or left end (Fig. 2) the heating element housing isprovided with an upwardly extending nose 92, which has a tapered bore93. The tapered bore extends downwardly and slightly forwardly andterminates in a counterbore 94, which has the bronze nozzle 95 fixedlysecured therein by a close frictional or drive fit. The nozzle 95continues the taper of the bore 93 to a relatively fine nozzle opening85, which determines the amount of metal sprayed from the gun.

The tapered bore 93 is adapted to receive a stick of suitable solder 91,which is melted by heat of the body 81 generated in the heating coil 82.The brass air tube 68 also terminates in ,a nozzle 98, the shape ofwhich is Shown in Fig. 7. This air tube nozzle opening comprises an arcin shape, and is formed by flattening the end of the tube and curvingit. It curves about the ta pered frusto-conical end 99 of the airnozzle, when viewed in elevation in Fig. 7. The forward wall Hill of theheater element housing 81 is provided with an aperture Illl for passingthe air nozzle tube 66.

The end I02 of the nose of the gun is suitably curved so that it may beused as a trowel'i'or smoothing out the solder after it has been placedand during the placing of the solder. It will be understood that thisnose surface I02 is very hot and is adapted to remelt the placed solder,if necessary, in order to smooth it out and place it properly, but thesolder is primarily placed by means of the spraying operation.

The edges of the heating element housing 81 where they engage the valvehousing 55 are provided at the points I03 with a plurality of small-hemi-spherical projections. These projections tion. The gun ispermitted to heat up for a period 01' five minutes. When a metal solderstick, touched to the nose of the gun, is melted, hen the gun is hotenough to work. During this 'ime some air will be heard to pass throughthe gun on account of the initial clearance given the air valve if theair tube is connected at this time. The surface of the metal to besprayed must be sanded absolutely clean, preferably with a disc sander,and the area sanded should extend to about one inch around the metalfill. All hammering and bumping out of the area should be done beforeapplying the metal. Use of acid or paint remover should be avoided inall cases.

I When the surface has been cleaned, a cold tnning compound, suitablefor the type of metal cleaned, is used to tin the surface of the metal.Various tinning compounds are on the market and may be used, but I deemit of great importance to use the tinning compounds and methodsdescribed in the co-pending application of Frank Osbem Albertson andGustav A. Olsen, Ser. No. 80,372, filed May 18, 1936, on Method andcomposition for spraying metal. The tinning compound is applied bywetting a felt base applicator and rubbing the compound into thesurface. Then the compound is wiped off to a clean, bright finish bymeans of a cloth, leaving an amalgam of mercury on the surface. The gunmay be properly heated and connected tga sourceof air pressure of from55. to pounds per square inch. It is now in condition to be used. Onlydry air should be used. and water should be carefully drained from theair line. The metal well in the gun should be kept clean, and if notclean should be cleaned out before spraying. This is done by means of asteel blow-out tool, shown in Fig. 8. This clean-out tool H8 has atapered body ill, fitting the metal well, and a laterally turned end H2,with a ball-shaped depression H3.

The depression H3 may be disposed in front of the air nozzle, as shownin Fig. 9, to force air from that nozzle up into the metal well to blowit out.

"The solder stick is thenfed into thewell of the heat gun, and as it ismelted it is sprayed by means of the compressed air from the nozzle 98.Pressure of the trigger controls the supply of the air, and when thetrigger is released both the heat unit and the air are automaticallyshut oil. This avoids damage to the gun. The nose of the gun should notbe held too far away from the work, and the best results areaccomplished by holding the gunat from one to two inches from the work.

The best way tospray the metal filling is first to spray a thin layer ofmetal, covering the entire tinned surface. The spray should be moved incircular motion around the outer edge and toward the center. The airshould be kept on all the time while feeding metal to the gun. Thistends to prevent blowing a blotch of molten metal on the job, and if ablotch occurs it should be removed. When more than one place is to berepaired, the places should be tinned and sprayed one at a time, Thespray dust resulting from one job and covering the second preparedsurface should be wiped oil before tinning the second place.

The metal filling should be sanded down to a feather edge, and inplacing the metal it should be built up to such a depth that it can besanded down to a smooth surface. It is better to use suflicient metal sothat it is not necessary to try to add metal after the surface has beenonce polished. The metal adheres better when it is more thoroughapplications of the tinning compound to the lead surface and immediatelyspraying metal on it as described in said copending application.

The gun should be carefully cleaned, particularly at the metal well,while it is hot, and the nozzle should be blown out at that. time, afterall metal has been removed from the well.

.The present metal spray gun is adapted to be used to carry out animproved method of repair of automotive fenders and bodies. The presentgun has a more effective control than any of the spray guns of any typeof the prior art, and both the air and heat are controlled by thetrigger. The metal sprayed by this gun is so cool that it may bedirectly sprayed upon anything without heating the body to which thespray is applied. Thus the panels of metal composing the vehicle bodyare not heated and warped, and there is no danger of ignitinginflammable material used under the metal body for insulation.

The present gun is kept cool by means of its improved structure and bymeans of the valve clearance which utilizes the air pressure to efiect acooling. It is also adapted to be used for a long period of time withoutoverheating or damage to any of its parts.

While I have illustrated and described a preferred embodiment of myinvention, many modifications may be made without departing from thespirit of theinvention, and I do not wish to be limited to the precisedetails of construction set forth, but desire to avail myself of allchanges within the scope of the appended claims.

Having thus described my invention, what I claim as new and desire tosecure by United D States Letters Patent is:

1. In a metal spray gun, the combination of an electric heating elementwith a body having a metal well with a discharge aperture, an air nozzlefor spraying molten metal discharged through said aperture, electricswitch means for controlling the supply of electric current to saidheating element, valve means for controllingthe supply of air to saidair nozzle, and common controlling means whereby the air supply and theheat of the element are both controlled from the same manual means, saidair valve having an initial clearance permitting the leakage of airthrough said gun and nozzle to effect a cooling of said gun.

2. In a metal spray gun, the combination of an electric heating elementwith a body having a metal well with a discharge aperture, an air nozzlefor spraying molten metal discharged through said aperture, electricswitch means for controlling the supply of electric current to saidheating element, valve means for controlling the supply of air to saidair nozzle, and common controlling means whereby the air supply and theheat of the element are both controlled from the same manual means, saidcommon controlling means being arranged in such manner that the initialmovement of said controlling means closes the electric circuit andfurther movement of said controlling means controls the opening of saidair valve.

3. In a metal spray gun, the combination of an electric heating elementwith a body having a metal well with a discharge aperture, an air nozzlefor spraying molten metal discharged through said aperture, electricswitch means for controlling the supply of electric current to saidheating element, valve means for controlling the supply of air to saidair nozzle, common controlling means whereby the air supply and the heatof the element are both controlled from the same manual means, and meansfor latching said common a controlling means with the switch in closedposition to heat up the gun.

4. In a metal spray gun, the combination of an electric heating elementwith a body having a metal well with a discharge aperture, an air nozzlefor spraying molten metal discharged through said aperture, electricswitch means for controlling the supply of electric current to saidheating element, valve means for controlling the supply of air to saidair nozzle, common controlling means whereby the air supply and the heatof the element are both controlled from the same manual means. saidcommon controlling. means being arranged in such manner that the initialmovement of said controlling means closes the electric circuit andfurther movement of said controlling means controls the opening of saidair valve, and means for latching said common controlling means withthe. switch in closed position to heat up the gun.

5. In a metal spray gun, the combination of a supporting handle with aplurality of posts for supporting a gun body, said posts supporting saidgun body in spaced relation to said handle, a gun body comprising meansfor housing an air valve, and means for housing an electric heatingelement, said latter means being constructed of heat conducting metaland being provided with a metal well whereby a supply of metal insertedin said well is melted to be sprayed from said gun.

6. In a metal spray gun, the combination of a supporting handle with aplurality of posts for supporting a gun body, said posts supporting saidgun body in spaced relation to said handle, a gun body comprising meansfor housing an air valve,

and means for housing an electric heating element, said latter meansbeing constructed of heat conducting metal and being provided with ametal well whereby a supply of metal inserted in said well is melted tobe sprayed from said gun, and said metal well having a metal nozzleconstructed of metal having a high melting point.

'7. In a metal spray gun, the combination of a supporting handle with aplurality 'of posts for supporting a gun body, said posts supportingsaid gun body in spaced relation to said handle, a gun body comprisingmeans for housing an air valve, means for housing an electric heatingelement,

said latter means being constructed of heat conducting metal and beingprovided with a metal well whereby a supply of metal inserted in saidwell is melted to be sprayed from said gun, said metal well having ametal nozzle constructed of metal having a high melting point, and anair tube controlled by said valve and extending through said gun bodyand having a nozzle disposed in proximity to said well nozzle.

8. In a metal spray gun, the combination of a supporting handle with aplurality of posts for supporting a gun body, said posts supporting saidgun body in spaced relation to said handle, a gun body comprising meansfor housing an air valve, means for housing an electric heating element,said latter means being constructed of heat conducting metal and beingprovided with a metal well whereby a supply of metal inserted in saidwell is melted to be sprayed from said gun, said metal well having ametal nozzle constructed of metal having a high melting point, an airtube controlled by said valve and extending through said gun body andhaving a nozzle disposed in proximity to said well nozzle, and commoncontrolling means carried by said handle for controlling the opening ofsaid valve and the connection of said heating element to a source ofelectric power.

9. In a metal spray gun, the combination of a heat conducting bodyformed with a downwardly tapering metal well, said metal wellcommunicating with a counterbore and a bronze metal nozzle located insaid counterbore, said body having a substantially trough shaped chamberin its lower side provided with a closure plate and a porcelain supportlocated in said chamber and a heating element on said support, saidporcelain support and said chamber having complementary engagingshoulders to prevent rotation of said porcelain support in said chamber.

10. In a metal spray gun, the combination of a heat conducting bodyformed with a downwardly tapering metal well, said metal wellcommunicating with a counterbore and a bronze metal nozzle located insaid counterbore, said body having a substantially trough shaped chamberin its lower side provided with a closure plate, a porcelain supportlocated in said chamber, a heating element on said support, saidporcelain support and said chamber having complementary engagingshoulders to prevent rotation of said porcelain support in said chamber,a second metal body fixedly secured to said first metal body andcarrying the first metal body, and means between said metal bodies forspacing them from each other to reduce the heat conduction between saidmetal bodies.

11. In a metal spray gun, the combination of a heat conducting bodyformed with a downwardly tapering metal well, said metal wellcommunicating with a counterbore and a bronze metal nozzle located insaid counterbore, said body having a substantially trough shaped chamberin its lower side provided with a closure plate, a porcelain supportlocated in said chamber, a heating element on said support, saidporcelain support and said chamber having complementary engagingshoulders to prevent rotation of said porcelain support in said chamber,a second metal body fixedly secured to said first metal body andcarrying the first metal body, means between said metal .bodies forspacing them from each other to reduce the heat conduction between saidmetal bodies, said second metal body having an air tube fixedly carriedthereby, said air tube extending through said porcelain support andcarrying the porcelain support, and a nozzle carried by said metal tubeadjacent said well nozzle to effect a spray of metal discharging fromsaid well nozzle.

12. In a metal spray gun, the combination of a heat conducting bodyformed with a downwardly tapering metal well, said metal wellcommunicating with a counterbore and a bronze metal nozzle located insaid counterbore, said body having a substantially trough shaped chamberin its lower side provided with a closure plate, a porcelain supportlocated in said chamber, a heating element on said support, saidporcelain support and said chamber having complementary engagingshoulders to prevent rotation of said porcelain support in said chamber,a second metal body fixedly secured to said first metal body andcarrying the first metal body, means between said metal bodies forspacing them from each other to reduce the heat conduction between saidmetal bodies, valve means for controlling the flow of air through saidmetal tube, and electric switch means for controlling the connection ofthe source of heat supplied to said element.

13. In a metal spray gun, the combination of a heat conducting bodyformed with a downwardly tapering metal well, said metal wellcommunicating with a counterbore and a bronze metal nozzle located insaid counterbore, said body having a substantially trough shaped chamberin its lower side provided with a closure plate, a porcelain supportlocated in said chamber, a heating element on said support, saidporcelain support and said chamber having complementary engagingshoulders to prevent rotation of said porcelain support in said chamber,a second metal body fixedly secured to said first metal body andcarrying the first metal body, means between said metal bodies forspacing them from each other to reduce the heat conduction between saidmetal bodies, said second metal body having an air tube fixedly carriedthereby, said air tube extending through said porcelain support andcarrying the porcelain support, a nozzle carried by said metal tubeadjacent said well nozzle to efiect a spray of metal discharging fromsaid well nozzle, and a common trigger for controlling both said valvemeans and said electric switch means.

14. In a metal spray gun, the combination of a heat conducting bodyformed with a downwardly tapering metal well, said metal wellcommunicating with a counterbore and a bronze metal nozzle located insaid counterbore, said body having a substantially trough shaped chamberin its lower side provided with a closure plate, a porcelain supportlocated in said chamber, a heating element on said support, saidporcelain support and said chamber having complementary engagingshoulders to prevent rotation of said porcelain support in said chamber,a second metal body fixedly secured to said first metal body andcarrying the first metal body, means between said metal bodies forspacing them from each other to reduce the heat conduction between saidmetal bodies, said second metal body having an air tube fixedly carriedthereby, said air tube extending through said porcelain support and.carrying the porcelain support, a nozzle carried by said metal tubeadjacent said well nozzle to effect a spray of metal discharging fromsaid well nozzle, a common trigger for controlling both said valve meansand said electric switch means, and latching means for latching saidtrigger in closed circuit position.

FRANS 0. ALBERTSON.

